Publications of The Korean Astronomical Society (천문학논총)

The Korean Astronomical Society (한국천문학회)
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EVIDENCE FOR THE SOLAR CYCLE IN THE SUNSPOT AND AURORA RECORDS OF GORYER DYNASTY

고려시대의 흑점과 오로라 기록에 보이는 태양활동주기

  • YANG HONG JIN (Department of Astronomy and Atmospheric Science, Kyungpook National University) ;
  • PARK CHANGBOM (Department of Astronomy, Seoul National University) ;
  • PARK MYUNG GOO (Department of Astronomy and Atmospheric Science, Kyungpook National University)
  • 양홍진 (경북대학교 천문대기과학과) ;
  • 박창범 (서울대학교 천문학과) ;
  • 박명구 (경북대학교 천문대기과학과)
  • Published : 1998.12.01
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Abstract

We have analyzed the sunspot and aurora data recorded in Go-Ryer-Sa. We have collected 35 records of sunspot observations for 46 days, and 232 records of auroral observations. To objectively estimate the periods of the solar activity appearing in these records a method of calculating the one-dimensional power spectrum from inhomogeneous data is developed, and applied to the sunspot and auroral data. We have found statistically significant 10.5 and 10 year periodicities in the distributions of sunspot and aurora records, respectively. These periods are consistent with the well-known solar activity cycle. There are indications of the long-term variations, but the period is not certain. We have also calculated the cross-correlations between the sunspot and auroral data. In particular, we have divided the aurora data into several subgroups to study their nature. We conclude that the historical records of strong auroral activity correspond to non-recurrent magnetic storms related to the sunspots. On the other hand, the records of weak auroral activity are thought to be related with the recurrent magnetic storms which occur frequently due to the coronal hole near the sunspot minimum.

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